Generally, after a display panel is manufactured, the display panel needs to be detected to determine whether the display panel has defects or not. In order to facilitate detection, test pads are usually arranged on a display substrate (generally an array substrate), and during detection, test probes are used to contact test points on the test pads, and the test points are connected with signal lines, so that detection signals can be input to the signal lines through the test probes and the test points to detect whether the display panel has defects or not.
FIG. 1 shows a schematic diagram of a display substrate in the prior art, and FIG. 2 shows a schematic diagram of test pads in the display substrate shown in FIG. 1. As shown in FIGS. 1 and 2, a driver chip IC is arranged at a marginal area of the display substrate 1, signal lines for connecting the driver chip IC with pixel units of the display substrate are arranged between the driver chip IC and the pixel units of the display substrate, test pads 2 are arranged on two sides of the driver chip IC, and the test pads 2 are connected with the signal lines. Moreover, a flexible circuit board 3 is further arranged at the edge of the display substrate 1, and the flexible circuit board 3 is used for connecting the display substrate 1 with a printed circuit hoard (not shown in the figures).
In the above display substrate 1, an exposed conductive metal area on each test pad 2 is generally used as a test point, which is easily corroded in the atmospheric environment, and corrosion of the test point can cause signal abnormity in the signal lines and thus can cause damage to the tested display panel. Therefore, after the display panel is detected, the test pads 2 need to be coated with UV adhesive to avoid corrosion of the test points. Obviously, coating the test pads 2 with the UV adhesive can reduce the production efficiency of the display substrate and the display panel including the display substrate, and reduce the productivity, and also, can result in increased thicknesses of the display substrate and the display panel including the display substrate.